It is common to mark certain objects such as guns, ammunition or valuables to be able to identify individual objects or to authenticate an object. Generally, the intention can be to apply a mark to an object which mark is unique, comparable to a fingerprint, can be easily recognized and, thus, allows for easy identification or authentication of the object. In this regard, it is an important aim that the mark cannot be copied or counterfeited in as much as possible.
Today, marking solutions are based on unique materials, patterning or physical properties of a mark. Such marks are usually created by printing technology, laser engraving or mechanical engraving. Most of these marks are generated from predetermined code, applied in the form of symbols, and reconfirmed by a reading and identification process. However, such marks can often be copied or counterfeited. This is, because the technology for applying the mark on the basis of a predetermined code can usually also be used by an unauthorized person for counterfeiting or copying the mark. The predetermined code usually is not really random. Only very few marking processes are suitable for producing marks of naturally random characteristics. These processes would have to rely on chaotic dynamic processes in order to be suitable to produce a really random mark. Known random features rely on random arrangement of fibres, bubbles, stains or flakes, which are produced by printing technology or naturally occurring during the manufacturing process. However, most of these processes can hardly be applied to products having a metallic surface, such as guns, ammunition or containers made of metal.
A usual marking technology for marking such objects is laser engraving. Laser engraving technology usually is based on pseudo-random features, wherein the randomness is created by a numerical generator, but not based on chaotic physical phenomena. Further, it is possible to copy such marks by also using laser engraving technology.
MD 3389 F2 discloses a method and apparatus to mark electrically conductive products in a random way using a welding type electrical arc and a vibrator to create randomness. According to this document, material from an electrode is transferred onto a pre-machined grid of the object to be marked to obtain a random mark. A randomness of the mark, which consists of deposited metal on the surface of the object, is obtained by vibrating the electrode and translating the product relative to the electrode. Here, the electrode opposed to the object to be marked is the “cathode” (−) in the electrical circuit, whereas the object to be marked is the “anode” (+). This results in material to be transferred from the electrode towards the surface of the object.
However, also this principle does not result in a true random marking because the vibration of the electrode is controlled and can generally be copied. Further, this method requires extra material of the electrode to be consumed upon forming the mark. The method of the prior art is complicated because of the necessary grid and it requires the surface of the object to be pre-treated.
Accordingly, there is a need for a marking method and respective system for marking objects having a surface of a conductive material, such as metal objects, which allow for uniquely marking objects in a way that cannot be copied or counterfeited.